Radio Resource Management (RRM) is used in modern wireless communication networks to optimize the network capacity while at the same time achieving a high network performance from the perspective of a user terminal. RRM comprises multiple functionalities at different protocol layers of the telecommunication network. The RRM functionalities include, among others, power control (Layer 1), link adaptation (Layer 2) and admission control (Layer 3).
Discontinuous transmission (DTX) and discontinuous reception (DRX) are measures that may beneficially be implemented in the RRM context or in similar contexts such as the management of power resources. In general, DTX and DRX help to minimize the power consumption of user devices and, in the case of battery-operated user devices, to maximize their operating times.
As an example of a DRX scheme, the 3rd Generation Partnership Project (3GPP) defines in its Long Term Evolution (LTE) specifications micro-sleep periods during the active state of a user device. In the micro-sleep periods the user device refrains from monitoring the Physical Downlink Control Channel (PDDCH) for given subframes and enters a power saving mode instead.
FIG. 1 schematically illustrates a DRX cycle as defined in Section 3.1 of 3GPP Technical Specification (TS) 36.321 V.8.7.0 of September 2009. In brief, each DRX cycle comprises a so-called On-Duration as well as an idle period following the On-Duration. The DRX idle period can be considered as a pause that provides an opportunity for initiating power saving measures.